UltraSPARC T2

UltraSPARC T2 processor

T2 microprocessor floorplan

The T2 is a commodity derivative of the UltraSPARC series of microprocessors, targeting Internet workloads in computers, storage and networking devices. The processor, manufactured in 65 nm, is available with eight CPU cores, and each core is able to handle eight threads concurrently. Thus the processor is capable of processing up to 64 concurrent threads. Other new features include:[1]

• Speed bump for each thread, which increased the frequency from 1.2 GHz to 1.6 GHz
• One PCI Express port (x8 1.0) vs. the T1's JBus interface
• Two Sun Neptune 10 Gigabit Ethernet ports (embedded into the T2 processor) with packet classification and filtering
• L2 cache size increased to 4 MB (8-banks, 16-way associative) from 3 MB
• Improved thread scheduling and instruction prefetching to achieve higher single-threaded performance
• Two integer ALUs per core instead of one, each one being shared by a group of four threads
• One floating point unit per core, up from just one FPU for the entire chip
• Eight encryption engines, with each supporting DES, Triple DES, AES, RC4, SHA1, SHA256, MD5, RSA-2048, ECC, CRC32
• Hardware random number generator
• Four dual-channel FBDIMM memory controllers

There are 8 stages for integer operations, instead of 6 in the T1.

The T2 processor can be found in the following products from Sun and Fujitsu Computer Systems:

• Sun/Fujitsu/Fujitsu Siemens SPARC Enterprise T5120 and T5220 servers
• Sun Blade T6320 Server Module
• Sun Netra CP3260 Blade
• Sun Netra T5220 Rackmount Server

Sun also licensed the T2 processor to Themis Computer, which introduced the first non-Sun T2-based servers in 2008:

• Themis T2BC Blade Server, which supports the entire family IBM BladeCenter chassis [2]

UltraSPARC T2+ processor

In April 2008, Sun released servers based on the UltraSPARC T2 Plus processor, an SMP capable version of UltraSPARC T2.[3]

Sun released the UltraSPARC T2 Plus processor with the following changes:

• Ability to be used in 2 or 4 processor configurations (first CoolThreads processor capable of multi-processor capability)
• Loss of on-chip embedded 10 Gigabit Ethernet controller

Like the T1, the T2 supports the Hyper-Privileged execution mode. The SPARC Hypervisor runs in this mode and can partition a T2 system into 64 Logical Domains, and a two-way SMP T2 Plus system into 128 Logical Domains, each of which can run an independent operating system instance.

The UltraSPARC T2 offers a variety of performance improvements over the former UltraSPARC T1 processor

• Integer throughput and throughput/watt (>2x improvement)
• Integer single-thread performance (>1.4x improvement)
• Better floating-point throughput (>10x improvement)
• Better floating-point single-thread performance (>5x improvement)
• Increased performance of cryptography through additional cyphers included in the embedded crypto cores
• Two world-record single-chip SPEC CPU results, based on tests that delivered 78.5 SPECint_rate2006 and 62.3 SPECfp_rate2006

Leveraging the massive amount of thread-level parallelism (TLP) available on the CoolThreads platform can require different application development techniques than for traditional server platforms. Using TLP in applications is key to getting good performance. Sun has published a number of Sun BluePrints to assist application programmers in developing and deploying software on T1 or T2-based CoolThreads servers. The main article, Tuning Applications on UltraSPARC T1 Chip Multithreading Systems,[5] addresses issues for general application programmers. There is also a BluePrints article on using the Cryptographic Accelerator Units on the T1 and T2 processors.[6]

Peak power consumption can go as high as 123 watts, but the T2 typically consumes 95 watts during nominal system operation. This is up from 72 watts from the T1. Sun explains that this is due to a higher degree of system integration onto the chip.

On April 12, 2006, Sun announced the tape-out of the UltraSPARC T2.[15] Sun announced the T2's release on 7 August 2007, billing it as "the world's fastest microprocessor".[16]

On April 9, 2008, Sun announced the UltraSPARC T2 Plus.

On December 11, 2007, Sun made the UltraSPARC T2 processor design publicly available under the GNU General Public License via the OpenSPARC project. The release includes:

• Verilog RTL source code of the design
• Verification environment
• Diagnostics tests
• Open source tools, scripts and Sun internal tools needed to simulate the design
• ISA specification (UltraSPARC Architecture 2007)
• Solaris 10 OS simulation images

• OpenSPARC T2 and Specifications
• OpenSPARC Overview
• CMT Comes Of Age: Sun engineers give the inside scoop on the new UltraSPARC T2 systems
• CoolThreads Overview
• Niagara II: The Hydra Returns